yeah after looking a bit deeper into it i figured as much. Hmm maybe since pack converts into double-precision representation as it is provided by your system it would be possible to fool perl into believing double precision would take 80 bytes instead of 64?

I'm reading through the POD of the Config Module as i write this and found the variables d_dbl_digit and d_ldbl_digit to be interesting. but it seems the Config module only supplies readonly access to those variables :/